Interhemispheric Coupling Study by Observations and Modelling (ICSOM): Concept, Campaigns, and Initial Results
Interhemispheric Coupling Study by Observations and Modelling (ICSOM): Concept, Campaigns, and Initial Results
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DOI：
10.1029/2022jd038249
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发表时间：
2016-03
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通讯作者：
Kaoru Sato;Y. Tomikawa;M. Kohma;Ryosuke Yasui;D. Koshin;H. Okui;S. Watanabe;K. Miyazaki;M. Tsutsumi;D. Murphy;C. Meek;Yufang Tian;M. Ern;G. Baumgarten;J. Chau;X. Chu;R. Collins;P. Espy;H. Hashiguchi;A. Kavanagh;R. Latteck;F. Lübken;M. Milla;S. Nozawa;Y. Ogawa;K. Shiokawa;M. Alexander;Takuji Nakamura;W. Ward
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文献类型：
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作者：
Kaoru Sato;Y. Tomikawa;M. Kohma;Ryosuke Yasui;D. Koshin;H. Okui;S. Watanabe;K. Miyazaki;M. Tsutsumi;D. Murphy;C. Meek;Yufang Tian;M. Ern;G. Baumgarten;J. Chau;X. Chu;R. Collins;P. Espy;H. Hashiguchi;A. Kavanagh;R. Latteck;F. Lübken;M. Milla;S. Nozawa;Y. Ogawa;K. Shiokawa;M. Alexander;Takuji Nakamura;W. Ward
一个题为“通过观测和建模进行的半球间耦合研究”的国际联合研究项目正在进行中。在2000年代后期，人们发现了一种有趣的半球间耦合（interhemispheric coupling，IHC）形式：当冬季极地平流层变暖时，夏季半球的上层中间层也会变暖，但会滞后几天。这种IHC现象被认为是通过中层大气（即，平流层、中层和低热层）。到目前为止，已经提出了几种可能的机制，但它们仍然存在争议。这主要是因为在小尺度上观测和模拟重力波（GWs）的困难，尽管它们在中层大气动力学中扮演着重要的角色。在该项目中，通过将稀疏但全球分布的雷达联网，自2015/16年以来，在七个北方冬季同时观测到了中间层GW。我们已经成功地捕获了五次平流层突然变暖事件和两次极涡增强事件。该项目还包括开发一个新的数据同化系统，以生成整个中层大气的长期再分析数据，并使用再分析数据作为初始值，通过最先进的GW允许的大气环流模式进行模拟。通过分析这些观测数据，数据同化和模式模拟，综合研究调查IHC的机制计划。本文概述了ICSOM，但即使是初步结果也表明，不仅GW而且大尺度波对于IHS的机制也很重要。
An international joint research project, entitled Interhemispheric Coupling Study by Observations and Modelling (ICSOM), is ongoing. In the late 2000s, an interesting form of interhemispheric coupling (IHC) was discovered: when warming occurs in the winter polar stratosphere, the upper mesosphere in the summer hemisphere also becomes warmer with a time lag of days. This IHC phenomenon is considered to be a coupling through processes in the middle atmosphere (i.e., stratosphere, mesosphere, and lower thermosphere). Several plausible mechanisms have been proposed so far, but they are still controversial. This is mainly because of the difficulty in observing and simulating gravity waves (GWs) at small scales, despite the important role they are known to play in middle atmosphere dynamics. In this project, by networking sparsely but globally distributed radars, mesospheric GWs have been simultaneously observed in seven boreal winters since 2015/16. We have succeeded in capturing five stratospheric sudden warming events and two polar vortex intensification events. This project also includes the development of a new data assimilation system to generate long‐term reanalysis data for the whole middle atmosphere, and simulations by a state‐of‐the‐art GW‐permitting general circulation model using the reanalysis data as initial values. By analyzing data from these observations, data assimilation, and model simulation, comprehensive studies to investigate the mechanism of IHC are planned. This paper provides an overview of ICSOM, but even initial results suggest that not only GWs but also large‐scale waves are important for the mechanism of the IHC.